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<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>循环作用域(使用let关键字)</title>
</head>

<body>
    <h2>JavaScript let</h2>
    <p id="demo"></p>
    <script>
        var i = 5;
        for (let i = 0; i < 10; i++) {
            //一写代码...
        }
        document.getElementById("demo").innerHTML = i;
    </script>
</body>

</html>